I am fitting 12 interlinked mains detectors all with battery backup.
I have a choice of three for each of the 12 locations in the house.
They are optical, ionisation and heat.
The 12 locations are kitchen, garage, loft, 5 bedrooms, lounge, dining, hall and landing.
I'm using heat detectors in the kitchen and garage. i plan to use ionisation elsewhere for the rest of the house. The loft will be an ionization type as there will be servers, multiswitches and network switches in there as well as the power and lighting. Ionisation as I understand it is best for electrical fires.
Now which is the best choice of detector for a lounge that is 3m by
4m that has a wood burning stove, giving the best compromise between false alarms and maximising chances of being alerted to a real unwanted fire.
are there any particular rooms that should have an optical detector instead of an ionisation type? if so, why?
I can't use more than 12 alarms interlinked (dicon and BRK range) I could use Kidde instead as that will go up to 24 interlinks but they are expensive in comparison to Dicon or BRK
there is a hall and a dining room adjacent to the lounge and I am putting ionisation detectors in these two rooms. The bedroom above the lounge will have an ionisation detector.
Do not use Kidde. Do use alarms with either 9V Lithium or permanent long life battery. Alkaline are a pain when you have a lot of alarms because they do cause annoying "low battery" signals typically at 4am in the morning and you have to hunt around to find which.
Why are you putting smoke alarm's in every room in the house? Multiple storey sprawling town house, difficulty in achieving required dB(A) measurement next to bed head?
- Hall Up
- Hall Down
- Kitchen - heat alarm
- Garage - heat alarm
- Loft - heat alarm
- Room with wood burner in
I would put the saving into fire blanket, 55B foam extinguisher (electric ok), 55B CO2 extinguisher (toast :-) on each floor.
I am deaf..... thats why and I can get a special alarm clock that detects the sound of smoke detectors but for it to work, there has to be a smoke detector physically in the same room as the special alarm clock.
So an ionisation detector is OK in the same room as wood burner?
CO detector (ideally also interlinked) - seem to remember noticing that any solid fuel stoves fitted after some date in 2010 should be backed up with CO detection as a new thing in the building regs. Even if your stove predates that date, it is a good idea.
Then add whichever of optical or ionisation would suit the room use best.
the audible recognition of the clock may not be infallible and it might be better to look for an attachment (vibrating alert?) that interfaces directly to the smoke detection system. The vibrating pads usually run off 12V.
At 12 detectors/sounders it might be worth looking at fire alarm panels, which can power almost unlimited number of sounders and strobes.
Ionisation are cheap but overly sensitive, and are best kept away from kitchens, garages, boiler rooms. If you're putting alarms everywhere, I'd include at least 1 or 2 opticals, since the 2 types respond well and poorly to different fire types.
Heat and rate of rise are the usual thing for boiler rooms, the latter being an improvement on the former. But both are far less effective at fire detection than the ionisation/optical.
Contrary to some opinions more does not always equal better when it comes to fire alarms. There is always a compromise between nuisance alarms and real fire alarms. Nuisance alarms are not false alarms but simply ones caused by normal activities which produce combustion products (cooking is the most obvious) . If when you cook the alarm tends to go off then people eventually ignore it or disable it.
The ideal is to have adequate alarms to detect the major fire risks quickly but not so many that nuisance alarms occur. In a two storey house the first priority should be an ionisation alarm on the ceiling at the top of the stairs. This is the alarm which will normally go off first for any fire starting downstairs.
Living and dining room alarms are normally not necessary unless you have open fires, wood burning stoves or someone who smokes. Bedroom alarms similarly are not usually helpful unless someone smokes or (as in your case) is deaf or hard of hearing in which case a combined sound and flash light type can be fitted to act simply as an alarm repeater (or see later for a better alternative).
Ionisation detects gaseous and usually invisible products of combustion. It is quite possible to have something like a smoothing capacitor fail in a computer and fill a room with smoke but for there to be no triggering of an ionisation detector. This isn't a problem, lots of smoke from a faulty component doesn't mean there is a particular risk of fire. Once something actually starts burning the ionisation detector will trigger. An optical detector in the same situation will tend to trigger earlier but is no "safer".
However, lofts are dusty places with insects and many particulate and ionisation alarms don't like that sort of atmosphere so you would be better fitting a rate of rise detector above the bits of electronics. Remember the aim of a fire alarm is to allow everyone to get out - not to stop the building burning down.
A rate of rise detector on the ceiling above the fire. Ionisation in the hall outside.
However, a lot depends upon how you use the fire and how old the house is. An old building with leaky windows and ill fitting doors will behave quite differently to a modern one with double glazed sealed windows and well fitting doors.
Each time you open the stove you are releasing combustion products into the room. In a well sealed room with few air changes these may trigger either an optical or ionisation detector.
Fitting detectors in each room (unless you have smokers) isn't usually beneficial. The vast majority of dangerous fires occur at night from discarded cigarette ends or in the kitchen (chip pans or cloths on stoves).
The number of detectors you are proposing, unless the building is of unusual construction, is rather on the high side. You may find the number of nuisance trips in operation to be excessive.
As part of the problem is alerting someone with no hearing a better solution might be to either use a dedicated system such as the one made by Bellman
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instead of a plethora of interlinked alarms wire individual sensors to a fire alarm panel such as :-
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can use such a panel with standard detector heads such as
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the panel has a number of alarm output options it is relatively easy to connect it to things like strobe lights in the bedroom
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to vibrating pads/bed shakers etc.
Carbon Monoxide has been mentioned. Unlike fire which poses an immediate risk the threat from CO tends to be more insidious, it is more important to be able to measure the level and be alerted if it starts going up over time (days) rather than trigger at a single set point. For that reason I would use something like
For interlinked that mostly leaves Aico or a full on commercial system - are there any other companies that make interlinked alarms?
It's an interesting problem that I am also tackling.
Would it not be wise to have smoke detectors in bedrooms that are full of running mains powered electronics (computers, tvs etc) and all the plugs and trailing cables entailed?
I'm thinking that should a small fire break out, the difference in time between a room alarm tripping and anough smoke getting into the hall to trip that one would be significant?
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